The present invention relates to a bookmaking method in a bookmaking system that aligns sheets printed by an image forming apparatus in a bundle on a tray in the proper page order and binds the sheet bundle to create a booklet.
Bookmaking apparatus are widely used as a terminal device of an image forming apparatus such as a printer or printing machine, to stack sheets formed with images in proper order, align the sheets into a booklet, apply adhesive to one edge of the stacked booklet and bind the stacked booklet to a cover sheet. On-demand printing systems, such as electronic publishing systems, are known that print and finish a predetermined booklet by printing predetermined information, automatically binding and covering the booklet and then cutting the edges of sheets.
Such a system is proposed in Japanese Patent Application Publication No. 2004-209869 that discloses creating automatically a booklet of sheets output from an image forming apparatus. Outputted sheets are received from a discharge outlet and guided to a discharge path, then stacked and stored in a tray disposed at a lower side of the discharge outlet. The sheet bundle stacked on the tray in a horizontal posture is turned 90 degrees, then guided in a vertical posture to an adhesive application unit for gluing. The glued sheet bundle is then glued to a cover sheet supplied from an inserter and folded around to the sheet bundle. After adhesion of the sheet bundle to the cover, sheet bundle sides not glued are trimmed to finish the booklet. The finished booklet is then stored in a stacker.
The 2004-209869 document further discloses a roller impregnated with adhesive that travels along a sheet bundle edge while applying adhesive to a sheet bundle held in a vertical posture. A gap is then formed between the adhesive roller and the edge of the sheet bundle, creating a build-up layer of adhesive, on the roller that is applied to the edge of the sheet bundle. Adhesive applied in this manner to the back or binding portion of the edge of the sheet bundle may under some conditions fail to seep between the sheets, resulting in sheets falling out of the booklet.
For that reason, Japanese Patent Publication No. 11-21006 discloses a method for applying adhesive by deforming and opening the sheet edges by pressing the adhesive roller and sheet bundle edge together.
Accordingly, one method of applying adhesive to a sheet bundle edge using an adhesive roller includes the formation of a gap, as small as tolerable, between the sheet bundle edge and the adhesive roller to apply adhesive while separated. A second method includes forcefully pressing the sheet bundle edge and adhesive roller together causing the sheets to deform and separate the sheets in order to apply the adhesive between the sheets.
Using the former method, adhesive is applied to the back or binding portion of the sheet bundle. However, because adhesive does not get between sheets, a problem of sheets becoming detached from the final booklet may arise. If the latter method is applied, adhesive does get between pages, but the cover sheet which is not applied with adhesive on the back of the sheet bundle partially adheres causing unevenness, so the problem of wrinkles forming on the back of the cover sheet occurs.
This invention provides a bookmaking method that securely adheres the sheets together when creating a booklet by covering a sheet bundle with a cover sheet, and securely and uniformly adheres a cover sheet to a backside of a sheet bundle edge without loss of aesthetic appeals of the booklets.